Abstract:
Chromium nanoparticles were first synthesised using planetary ball mill in wet environment. The
particle size was found to be nearly 60 nm, which was confirmed by X-ray diffraction (XRD),
scanning electron microscopy (SEM), transmission electron microscopy (TEM) and particle size
analyser techniques. Subsequently, Ni–20Cr alloy powder was synthesised by mechanical
alloying of micrometre sized Ni (80 wt-%) and presynthesised Cr (20 wt-%) nanosized powders.
X-ray diffraction revealed the solid solubility of Cr in Ni after ball milling for 20 h. The synthesised
Ni–20Cr powder was subsequently deposited on SA 516 by cold spraying process. The as
sprayed coatings were characterised by SEM/EDS, XRD, microhardness and porosity analyses. A
nanostructured Ni–20Cr coating could be developed with an average thickness of 225 mm and
microhardness of 335 HV having an apparent porosity of ,1?5%.
